Dishwashing machine



M y 1940- K. ALBRECHT DISHWASHING MACHINE Filed April 18, 1938 M INVENTOR l 5 fiw Patented May 14,1940

PATENT OFFICE msnwasnmo MACHINE Kurt Albrecht, Pittsburgh, Pa., assignor to John M. Hopwood, Mount Lebanon, Pa.

Application April 18, 1938, Serial No. 202,628

3 Claims.

This invention relates to mechanical dishwashing machines of the type utilizing a detergent wash solution, which is pumped from a solution tank through spray nozzles onto the dishes to remove soil, and employing rinse nozzles for spraying the dishes withplain rinse water after the soil has been removed by the washing action of the detergent solution.

In prior art machines of the type referred to above the construction and design was such that the rinse water discharged into the wash solution thereby diluting thesame and impairing, in some cases actually destroying, its efiectiveness. In some cases the solution in the tank would be changed as high as seventeen times per hour; obviously, unless an excess amount of detergent material was added to the tank, the wash solution would be diluted to only a fraction of its original strength. Therefore, to maintain the detergent solution at its proper strength or concentration, so much material had to be added to the solution that the cost of detergent material was excessive; while if detergent was not added, the concentration of the wash solution was,reduced so much that it was ineffective or so slightly effective that soil could not be be thoroughly removed from the dishes.

An object of this invention is to provide mechanical dishwashing machines with means whereby the concentration of thedetergent solution may be maintained at any desired value through suchcontrol of the rinse water that none of it, or only a small portion of it, is allowed to enter the detergent solution to dilute it.

Another object of the'invention is to provide means ,that may be made to function automatically to prevent dilution of the detergent washing solution when the supply of wash solution to the wash arms or nozzles is cut oil.

Other objects of the invention will, in part, be obvious, and will, in part, be apparent from the following description taken in conjunction with the accompanying drawing in which a mechanical dishwashing machine embodying one form of the invention is more or less diagrammatically illustrated.

The machine illustrated in the drawing comprises a wash chamber I provided with a perforated bottom or support 2 on which is a rack 3 containing dishes 4 to be washed.

The rack is placed in the machine through doors or openings 5 in position to be washed with a detergent solution which is sprayed over the dishes by means of a spray head or wash arm 6 having spray nozzles or jets 1 associated therewith.

The Wash solution is stored in a tank or receptacle 8 into which the solution is directed as it runs off the dishes through support 2. The wash solution is pumped from tank 8 by means of a motor-driven pump 9 and delivered through a pipe I!) to the spray head 6 at such pressure that the solution leaves nozzles I with sufficient velocity to efiect thorough and rapid removal of soil from the dishes.

When the dishes have been subjected to the washing action of the detergent solution for a sufficient length of time to insure removal of all soil, the dishes are rinsed with plain water. Before rinsing, however, the pump is stopped to shut on" the supply of wash solution to the spray head. Rins'mg may be effected by means of nozzles l or by a separate spray headand nozzle assembly. For the sake of illustration, it can 20 be assumed that nozzles l are also used for rinsing purposes. To utilize nozzles I for rinsing purposes, two valves H and I2 may be employed, valve H being closed (after pump 9 has been stopped), to prevent delivery of rinse water through pipe 80 to tank 8, and valve It being opened to connect spray head 6 to a rinse Water supply pipe l3.

In order to prevent dilution of the detergent solution by the rinse water, means I 4 are provided for intercepting the rinse water and directing it to a drain.

Means l4 comprises a plate or cover ISeXtending over the top of tank 8 having an opening l6 therein to which a tube I1 is connected, and an overflow tube or pipe l8 disposed within tube I1 and having its top located at a point well above the normal level IQ of the detergent wash solution of tank 8. The lower end of tube 18 is connected to a drain pipe 20.

Tube "extends downwardly from plate I5 to a point near the bottom of tank 8 and is substantially larger in diameter or crosssectional area than tube I8. Liquid, whether it be detergent wash solution or rinse water, falls on plate l5, which for practical reasons is so formed as to slope from-all sides towards opening [6.

When valve H is open (valve I! being then closed) and pump 9 is operatingto deliver wash solution to spray nozzles I, the level of the wash solution drops in tank 8 to a level such as indicated by line 2| so that as the wash solution falls from or. is delivered from chamber I onto plate IS, the liquid in running into the space between tubes I! and I8 will not overflow into. 55

' chamber I runs into opening l6 filling the space I1 and I8 which extends from approximately the and I8 so that the rinse water may overflow into not flow into the body of wash solution of tank tube l8. As soon as pump 9 is stopped the level will rise in tank 8 to say level l9. When rinse water is turned on to nozzles I, by closing valve I l andopening valve l2, the water discharging from to the body of solution in the receptacle, and a second passage disposed within the first-mentioned passage and which is open at a point. above above the liquid level I 9 and between tubes l1 receptacle and adapted to carry liquid overflowing into the same to a drain, whereby when said solution spraying means is operatin'g, said solution may flow from the wash chamber through I said first-mentioned passage to the solution tank and thence to the spray means, and when said solution spraying is stopped and rinse water is delivered to the wash chamber, the rinse water I8 and thence to drain via pipe 20. Because of the relatively long confined space between tubes top to the bottom of tank 8, rinse ,water will 8 and dilute it. The only dilution that can occur results from the relatively small amount of water that settles into the detergent solution confined n t at the t of said first mentjon d described above form in effect an automatic trap water to drain without diluting the detergent intercepting rinse water and passing it oil to detergents. Where no provision is made for pre- 4d provide a, solution of the desired and efiective concentration.- where dilution is controlled as ent is:

tively restricted passage extending from the;t0p

to tank without losing any solution through the between tubes I1 and I8 and that which is held on the surface of the column of fluid between them at levels below the top of tube l8. Plate l5 and tubes I! and I8 arranged as sage and ovr..'flows through vthe other passage to drain.

2. A wash solution supply receptacle for mechanical dishwashing machines of the jet-type or overflow that operates to allow free circulation adapted to be connected to pump supplying the of deter ent solution fr in tank to wash nozzl s g 0 e said jets, said receptacle having e closed top provided with an opening therein, a tube connected to said opening and extending downwardly into said receptacle for conveying return wash solution to the interior of said receptacle, and an overflow tube disposed within said first-mentioned tube in spaced relation thereto and having its upper end disposed above the normal level drain, and efiect automatic discharge of rinse solution. What little dilution that does occur is beneficial and not detrimental or wasteful of detergent.

yWhen a machine is provided with means for drain as above described, the concentration of the detergent wash solution can be maintained at its efiective value with small additions of detersaid overflow tube bein o e gent, thereby insuring economy in the use of g p rative to allow rinse water to collect in the space between said tubes on top of the wash solution and overflow into it to drain without substantially diluting said wash solution.

3. A wash solution supply receptacle for mechanical dishwashing machines orwthe jet type adapted to be connected to a pump supplying the Jets and receiving wash solution returned from said jets, said receptacle having a closed top provided with an opening therein and a tube conventing excess dilution, the wash solution in many cases undergoes as many as seventeen changes per hour requiring from ten to fifteen times as much detergent chemical as would be needed to herein described.

Having thus described the invention, what I claim as new and desire to secure by Letters Patinto said receptacle for conveying return wash solution to the interior of said receptacle, there being an overflow outlet associated with said tube the outlet opening of which is located above the normal level of wash solution contained in said receptacle, said overflow outlet being operative oqillow rinse water collecting in said tube on top of the'wash solution therein to overflow to 1. In a dishwashing machine provided with a wash chamber, a receptacle for detergent solution adapted to receive wash solution from the wash chamber, means for spraying dishes with wash solution from said receptacle, and means for delivering water to the sprayingumeans' for rinsing dishes in the wash chamber, the improve ment which is characterized by the fact that t wash solution receptacle is provided with a relfisolution.

KURT ALBRECHT.

to a point near the bottom thereof, through which wash solution is returned from the wash chamber the normal level of the wash solution in said Jets and receiving wash solution returned from r of wash solution contained in said receptable and having its lower end connected to a drain outlet, 7

nected to said opening. and extending downwardly drain without substantially diluting said wash 

